Interesting. My sight glass has a black circle on it that is about 1/2" in from the outer edge. That puts the line about 1/2" below the center of the glass, or 1/2" above. My understanding is the bottom of the sight glass is the reference point. Mine has been overfilled since I bought it, over 3yrs ago, and never caused an issue until about 2mos ago. Since then I've been monitoring it more closely, and it has yet to drop below the bottom line on the sight glass.
2005 Pace Arrow 36D
Very Understanding Wife
Hate to beat a dead horse, butttttt, the circle around the cover.the circle is the "minimum level" according to the inprint on the cover...so that tells me that is as low as the level should be...I will it keep it just below the rubber plug..wish Workhorse was still alive, so I could talk to a rep...so many answers on this forum
I assume that you don't like to use the Workhorse owner's manual, do you? It clearly says to add oil to bring it UP TO the level mark on the sight glass. It DOES NOT say fill it above the level mark. It DOES NOT say fill it up to the rubber plug. You can interpret things any way that you like but don't add words to what the Workhorse owner's manual clearly says.
I did read the manual and it says not to let the oil get below the minimum line around the cover...it doesn't say anything about a level mark, and there is no level mark on the sight glass...the mark on the cover is the minimum level..so many answers....soooooo
My Workhorse Manual W0004539A manual says fill to "level" and also has a picture. No question at all what the correct amount of oil is.